1. n. [Formation Evaluation]

The total pore volume per unit volume of rock. It is measured in volume/volume, percent or porosity units. The total porosity is the total void space and as such includes isolated pores and the space occupied by clay-bound water. It is the porosity measured by core analysis techniques that involve disaggregating the sample. It is also the porosity measured by many log measurements, including density, neutron porosity and nuclear magnetic resonance logs.

See: bound water,  effective porosity,  free water,  microporosity,  small-pore water